1. Field of the Invention
The invention relates to decorative laminates. More particularly, the invention relates to a method for producing decorative laminates incorporating a holographic image thereon.
2. Description of the Prior Art
High pressure decorative laminates are currently manufactured with smooth glossy surfaces, textured surfaces, or deeply sculpted and embossed surfaces. As general background, decorative laminates prepared by heat and pressure consolidation have been produced commercially for a number of years and have found widespread acceptance in the building and furniture industry as counter and tabletops, bathroom and kitchen work surfaces, wall paneling, flooring products, partitions and doors. These decorative laminates may be described as containing a number of laminae consolidated to form a unitary structure carrying a surface decoration. The surface decoration may range from something as simple as a solid color to something as complex as an embossed simulated wood grain finish.
Decorative laminates generally include plural layers of synthetic resin impregnated paper sheets bonded under heat and pressure to form a unitary structure. In normal practice, a decorative laminate sheet assembly, from the bottom up, includes a core of one or more phenolic resin impregnated sheets, above which lies a decorative resin-impregnated sheet. The decorative sheet may be further covered with a melamine-impregnated overlay.
The core, or base, functions to impart rigidity to the laminate. Prior to stacking, the sheets of the core member are impregnated with a water alcohol solution of phenol formaldehyde, dried and partially cured in a hot oven, and finally cut into shapes. The core may, for example, include a plurality of sheets of 41-68 kilogram phenolic resin impregnated kraft paper and a substrate. The kraft paper is impregnated throughout and bonded with a substantially completely cured phenolic resin which has been converted to a thermoset state during the initial laminating step.
The decorative sheet provides the laminate with an attractive appearance. The decorative sheet also dictates the surface characteristics of the decorative laminate. For example, the composition of the decorative sheet dictates the decorative laminate""s resistance to chemical agents, heat, light, shock and abrasion. Decorative sheets are commonly manufactured from high quality 80 to 200 g/m2 weight, pigment filled, alpha cellulose paper impregnated with a water alcohol solution of melamine-formaldehyde resin. The resin impregnated decorative sheets are subsequently dried, partially cured, and finally cut into sheets. The pigment filled, alpha cellulose paper of the decorative sheet, may include a solid color, a decorative design, or a photo-gravure reproduction of natural materials, such as, wood, marble, leather, etc. The aesthetic characteristics of the cellulose paper are revealed as the laminate""s decorative design upon completion of the decorative laminate.
Additional rigidity may be added to the decorative laminate through the bonding of a substrate to the formed decorative laminate. In general, the substrate may be a pre-cured plastic laminate, such as glass fiber-reinforced thermoset polyester resin laminates and the like, a wood product, such as hardboard, wood waste or particle boards, plywood and the like, a mineral base board, such as, cement-asbestos board, sheet rock, plaster board, and the like, or a combination of substrates.
Decorative laminates are generally manufactured by placing the resin impregnated core and decorative sheet between steel plates and subjecting the laminate stack to temperatures in the range of approximately 110xc2x0 C.-155xc2x0 C. and pressures in the range of about 56.24 kg/cm2-112.48 kg/cm2 for a time sufficient to consolidate the laminate and cure the resins (generally about 25 minutes to an hour). The pressure and heat force the resin in the paper sheets to flow, cure and consolidate the sheets into a unitary laminated mass referred to in the art as a decorative high pressure laminate. Finally, the formed decorative laminate is bonded to a reinforcing substrate, such as, plywood, hardboard, asbestos board, particle board or the like.
Generally, more than one laminate is formed at one time. Multiple laminates are formed by inserting a plurality of assembled sheets in a stack. Release sheets are positioned between the assembled sheets to separate the various laminates stacked together. After consolidation, the release sheets allow the individual laminates to be separated.
The above discussion generally relates to high pressure laminates. Where a less expensive, less durable laminate is required, low pressure laminates may be used by fabricators. Low pressure laminates are generally composed of only the decorative layer and the overlay. As with high pressure laminates, low pressure laminates may be secured to a substrate for added structural rigidity. The removal of the core results in a laminate which is cheaper to manufacture, but does not offer the strength and durability of high pressure laminates.
As mentioned above, the decorative sheet dictates the aesthetic appearance of the resulting decorative laminate. Prior decorative sheets range from vibrant colors to pure white, imitation wood to imitation granite, and many variations there between. The wide range of available designs provides consumers with a versatile, inexpensive product for fabricating countertops, flooring panels, wall panels, etc. The aesthetic appearance of the decorative laminate may be further enhanced by applying texture to the surface of the decorative laminate. The addition of such texture often provides the decorative laminate with a more natural appearance.
With this in mind, decorative laminate manufacturers and fabricators are continually attempting to develop laminates providing consumers with a new, aesthetically pleasing, visual experience. The present invention provides a decorative laminate offering consumers a novel visual experience by enhancing conventional decorative laminates with the addition of a holographic image.
It is, therefore, an object of the present invention to provide a decorative laminate lay-up including a decorative laminate sheet assembly having a top layer and a polypropylene release sheet applied to the top layer of the decorative laminate sheet assembly. The polypropylene release sheet is a cast polypropylene release sheet formed with a holographic transfer image.
It is a further object of the present invention to provide a decorative laminate manufactured by the process comprising the steps of stacking a decorative laminate sheet assembly having a top layer, casting a polypropylene release sheet wherein the polypropylene release sheet is formed with a holographic transfer image, positioning the polypropylene release sheet on the top layer of the decorative laminate sheet assembly, applying heat and pressure to the decorative laminate sheet assembly and the polypropylene release sheet sufficient to bond the decorative laminate and releasably bond the polypropylene release sheet to the top layer of the decorative laminate sheet assembly and removing the polypropylene release sheet from the top layer of the decorative laminate sheet assembly to reveal a decorative laminate exhibiting a desired holographic image.
Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention.